1. Field of the Invention
The subject invention relates to an electrical connector for mounting to a printed circuit board and for interconnecting to the electrical traces thereon, and more specifically to the retention feature which mounts the electrical connector to the printed circuit board.
2. Description of the Prior Art
There exists within the electronics industry electrical connectors which are right angled mounted to printed circuit boards, and for electrical interconnection to circuit traces on the printed circuit boards. One such problem involved in this industry relates to the mounting of the electrical connectors to the printed circuit boards. Typically, the electrical connectors are robotically inserted onto the printed circuit boards, and the assembly of the board and the connector is transferred to a wave soldering line where the electrical connector is soldered to the board. In addition to the terminals of the connector being interconnected to the printed circuit board, it is typical for a conductive retention feature to be commoned to the shield of the connector and then inserted into a through hole of the printed circuit board and soldered to a ground trace on the board.
In such an application where the retention feature is to common the shield to the printed circuit board, two considerations much be addressed. First, the retention feature must hold the connector squarely to the printed circuit board, in other words, the base of the connector must be held firmly to the printed circuit board such that the connector cannot rock on the printed circuit board. This assures that when the assembly of the printed circuit board and the connector are soldered to one another, the connector interface is parallel to the board. Typically, the datum line for electrical interconnections is the printed circuit board, thus a connector which is not properly aligned with the printed circuit board could actually preclude matability with the connector. For example, if the printed circuit board is interconnected to a right angled connector which is to mount within a personal computer, and the connector is to abut an outside wall of the chassis, if the connector is not properly aligned with the printed circuit board, when the printed circuit board is interconnected within the computer, the connector may not properly align with its intended connection port. This could result in a cable with a connector attached thereto which is not matable with the connector, or if it is matable, the connector must be forcibly aligned with the port which puts undue stresses on the printed circuit board connections.
Another aspect which is important for retention features is that they must provide adequate surface area for solderable interconnection thereto. When the retention feature projects through the printed circuit board through hole, the soldering of the retention member to the board provides the mechanical and electrical connection of the board to the connector. Increasing the surface area on the retention members to which the printed circuit board can be soldered, results in the strongest solder joint.
One such retention feature which is available is known as the split arrow and includes a flat stamping having members which are bent upwardly to form a flat locking feature which is parallel to the board. One problem with the split arrow approach is that since the locking member is flat or parallel to the board, the tolerance buildups between the connectors, boards and retention members can allow "play" between the connector housing and the board. This play can allow the connector to rock when the connector is placed on the board, such that when the board is soldered to connector, the connector and board are not parallel, resulting in the aforementioned problems.
The split arrow approach to board retention, as it is a flat stamping, allows little surface area for soldering thereto. The strength of a solder joint relates to the amount of solder deposited and the surface area of the solder interface. The solder interface on the split arrow retention feature is limited to the thickness of the flat metal stamping. When the mechanical stability of the connection system is limited to the strength of the solder joint, the electrical integrity of the interconnection can be jeopardized. For example, and again referring to the personal computer, if the connector and printed circuit board are placed at a port for exterior interconnection thereto, and the only mechanical stability is provided by the solder joints, the stepping on a cable which interconnects the printed circuit board mounted connector to the printer could disrupt the electrical integrity of the system.